The victims in the displays have been low-level cartel members — if they had cartel connections at all — meaning their killings offered little tactical advantage to their executioners. Instead, these public displays of violence are intended to convey messages to the public, to undermine their rivals' support bases and to put pressure from military and law enforcement on their rivals.

Narcomantas are useful for spreading disinformation, particularly when paired with large displays of corpses. This is because authorities rarely verify claims of authorship on narcomantas, which provides a low-risk opportunity for organized criminal groups to create a narcomanta and attribute it to whomever they wish. Typically, the cartels falsely attribute narcomantas to rivals to attract or deflect pressure from law enforcement or the military.

The well-publicized May 13 display of 49 dismembered bodies in Cadereyta, Nuevo Leon state, was followed two days later by narcomantas signed by Los Zetas in Zacatecas, San Luis Potosi and Nuevo Leon states denying Zetas involvement in the Cadereyta display. However, on May 18 the Mexican military detained local Zetas plaza boss Daniel de Jesus Elizondo Ramirez, also known as "El Loco," who is accused of orchestrating the display and who reportedly told authorities that Zetas leaders Heriberto "El Lazca" Lazcano Lazcano and Miguel "Z-40" Trevino Morales ordered the killings. He added that they hoped to pin the blame for the killings on their rivals.

The display of 49 bodies in the Zetas stronghold of Cadereyta would be unusual for the group, which typically employs significant displays of violence only in rival territory. Like any organized criminal group, the Zetas would not want to draw increased military operations to their territory by carrying out public displays of violence there. This and information from Stratfor sources that elements of the Gulf cartel carried out the Cadereyta massacre leaves who carried out the display unclear. Regardless of the who the culprits are, this event is marked by intentional disinformation, since only one message can be true: Either Los Zetas were framed, or the subsequent messages denying Los Zetas responsibility are a lie.

On May 4, 14 dismembered bodies were displayed outside the Association of Customs Agents in Nuevo Laredo with a narcomanta addressed to local officials and signed "El Chapo." Cartels such as Los Zetas that enjoy unchallenged operational control of a plaza typically receive support from local authorities. Los Zetas' rivals in Nuevo Laredo clearly hope to overcome this advantage by using tactics such as body dumps to terrify officials cooperating with Los Zetas into abandoning that support.

Mexico Weekly Map May 23, 2012

The cartels also use such displays to influence the general public. Cartels obtain recruits and extort money from the public. Knowing that Los Zetas have a challenger in the plaza, residents in Nuevo Laredo may become less inclined to support them since doing so could mean winding up in a body dump. Los Zetas responded in kind May 9 by displaying 18 dismembered bodies in the Sinaloa Federation stronghold of Guadalajara.

All signs suggest that the dueling body dumps will continue as Los Zetas, the Sinaloa Federation and their respective allies continue to wage an information operation campaign. Operations intended to undermine rivals as seen in Nuevo Laredo and operations intended to sow disinformation as seen in Cadereyta will continue, leaving what is actually going on more difficult to deduce.

May 14

Gunmen kidnapped the president of the local Chamber of Commerce in Chihuahua, Chihuahua state. At least four assailants intercepted the victim when he departed one of his hardware businesses in the Villa Juarez neighborhood.

May 15

Authorities discovered the body of a man in an abandoned truck in Culiacan, Sinaloa state. The truck bore the logo of an unidentified food production firm.

Unidentified gunmen shot and killed two men in a taxi in Ixtapa, Guerrero state. One of the bodies was wrapped in a narcomanta, but the authorities did not reveal what it said.

Authorities discovered the headless body of a woman in the Canteras neighborhood of San Pedro, Nuevo Leon state.

Suspected members of Los Zetas put up narcomantas denying their involvement in the killings of 49 people in Cadereyta, Nuevo Leon state. The banners appeared in Ciudad Valles, San Luis Potosi state, and Fresno, Zacatecas state.

Two gunmen were killed and two were injured in a confrontation between federal forces and gunmen in Guadalupe, Zacatecas state.

Authorities discovered a dismembered body in three bags on a bridge at the 96 kilometer (59 mile) marker of the Benito Juarez highway near Guamuchil, Sinaloa state. A narcomanta accompanying the body indicated the victim was a member of the Sinaloa Federation.

Gunmen and elements of the Mexican military engaged in a firefight in the Ocoroni community of El Fuerte, Sinaloa state. The gunmen managed to flee, though they abandoned one vehicle.

Unidentified gunmen attacked two taxi stops in Acapulco, Guerrero state. No deaths were reported in the attacks, but a group of gunmen set two vehicles on fire at a separate location after the first two attacks.

May 16

Four suspects stole 80 million pesos ($5.7 million) from a private bus terminal in Tuxtla Gutierrez, Chiapas state. A bystander who intervened was shot and killed. Police detained the suspected shooter, but three other suspects escaped.

Unidentified prisoners stabbed two brothers to death in a prison in Gomez Palacio, Durango state. The two men had been brought to the prison on May 14 on charges of "crimes against public health."

Police arrested eight suspected members of Los Zetas in Cadereyta, Nuevo Leon state. The men are believed to be responsible for at least 17 murders, including that of a bureaucrat in Cadereyta, but are not linked to the murders of the 49 people found in Cadereyta last week.

Authorities discovered five executed individuals in three separate locations in southern Guadalajara, Jalisco state. Authorities discovered a narcomanta accompanying two of the bodies.

Authorities discovered the dead body of a 26-year-old man hanging from a bridge in Torreon, Coahuila state. The body was semi-naked and hung from his hands, feet and neck.

Authorities discovered several narcomantas in various areas surrounding Monterrey, Nuevo Leon state, denying that Los Zetas were responsible for the murder of the 49 individuals displayed in Cadereyta, Nuevo Leon state, on May 13. The messages were addressed to Nuevo Leon state authorities.

Police in Chihuahua, Chihuahua state, freed the kidnapped head of the Chamber of Commerce during a raid on a house. Four gunmen were arrested.

Witnesses reported a military raid on a building in the Gustavo A. Madero neighborhood of Mexico City. No official announcement was made concerning the nature or target of the operation.

A group of gunmen in nine vehicles opened fire on a police station in Jerez de Garcia Salina, Zacatecas state. One police officer was wounded, one female shooter arrested and three vehicles seized. Authorities later learned the police chief of the municipality was the target of the attack.

Three gunmen were killed in a confrontation between Mexican marines and gunmen in Ostula, Michoacan state.

May 17

Unidentified people hung a narcomanta in Taxco, Guerrero state, and left a severed head under it. The narcomanta accused local officials of being involved with Los Rojos and La Familia Michoacana.

Authorities discovered a decapitated male body next to a vehicle in Los Mochis, Sinaloa state. The head was placed on top of the vehicle.

May 18

A third general was arrested in the investigation that previously led to two generals' arrests for alleged links to the Beltran Leyva Organization.

The Mexican army detained local Zetas plaza boss Daniel de Jesus Elizondo Ramirez in Cadereyta, Nuevo Leon state. Ramirez, also known as "El Loco," is accused of being connected to a display of 49 bodies May 13 in Cadereyta.

A confrontation between gunmen and the military along the Angostura-La Reforma highway near Guasave, Sinaloa state, resulted in the wounding of several gunmen and one marine. The confrontation began when one group tried to kidnap someone from the other group.

The Mexican military detained 13 alleged members of Los Zetas in San Andres Tuxtla, Veracruz state. All are accused of operating as halcones, or scouts.

May 19

A group of gunmen killed the director of public security in San Luis Rio Colorado, Sonora state, when he left home.

Gunmen executed two men inside a vehicle in Valle de Chalco, Mexico state.

Gunmen executed a taxi driver leaving his home in a rented vehicle in the 7 de Noviembre neighborhood of Veracruz, Veracruz state.

Six Zetas members were killed and two vehicles seized during a confrontation between federal police and members of Los Zetas in Concepcion del Oro, Zacatecas state.

The Mexican military seized a camp belonging to Cartel de Jalisco Nueva Generacion (CJNG) in Yurecuaro, Michoacan state, and detained one CJNG member.

May 20

Gunmen threw three grenades at the house of a former Tabasco state attorney general in Villahermosa, Tabasco state, wounding a police officer in the residence.

Authorities in Empalme, Sonora state, found three bodies in a grave at kilometer 112 of the Empalme-Vicam highway. The discovery was made after an anonymous phone tip of the bodies at that location.

May 21

Two gunmen were killed and a marine wounded in a clash between federal forces and gunmen in Xalapa, Veracruz state.

Gunmen on a motorcycle shot and killed a police chief in Guadalajara, Jalisco state, while he traveled in his SUV.

Unidentified people burned down El Amazonas Casino in Nuevo Laredo, Tamaulipas state. Authorities said arsonists used gasoline as an accelerant but that no one was injured. El Amazonas opened in February 2010, and reportedly is connected to Los Zetas. Even though federal authorities reportedly closed the casino in March 2012, witnesses said men routinely occupied the casino.

Police in Taxco, Guerrero state, found two severed heads with a message. The content of the message was not revealed.

Authorities discovered the dead bodies of two men in the La Constancia community of El Fuerte, Sinaloa state.